Abstract
Implementation of a Bayesian analysis of a selection experiment is illustrated using litter size [total number of piglets born (TNB)] in Danish Yorkshire pigs. Other traits studied include average litter weight at birth (WTAB) and proportion of piglets born dead (PRBD). Response to selection for TNB was analyzed with a number of models, which differed in their level of hierarchy, in their prior distributions, and in the parametric form of the likelihoods. A model assessment study favored a particular form of an additive genetic model. With this model, the Monte Carlo estimate of the 95% probability interval of response to selection was (0.23; 0.60), with a posterior mean of 0.43 piglets. WTAB showed a correlated response of -7.2 g, with a 95% probability interval equal to (-33.1; 18.9). The posterior mean of the genetic correlation between TNB and WTAB was -0.23 with a 95% probability interval equal to (-0.46; -0.01). PRBD was studied informally; it increases with larger litters, when litter size is >7 piglets born. A number of methodological issues related to the Bayesian model assessment study are discussed, as well as the genetic consequences of inferring response to selection using additive genetic models.
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Selected References
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- Legault C. Selection of breeds, strains and individual pigs for prolificacy. J Reprod Fertil Suppl. 1985;33:151–166. [PubMed] [Google Scholar]
- Roehe R. Genetic determination of individual birth weight and its association with sow productivity traits using Bayesian analyses. J Anim Sci. 1999 Feb;77(2):330–343. doi: 10.2527/1999.772330x. [DOI] [PubMed] [Google Scholar]
- Smith C., Dickerson G. E., Tess M. W., Bennett G. L. Expected relative responses to selection for alternative measures of life cycle economic efficiency of pork production. J Anim Sci. 1983 Jun;56(6):1306–1314. doi: 10.2527/jas1983.5661306x. [DOI] [PubMed] [Google Scholar]
- Sorensen D. A., Kennedy B. W. Analysis of selection experiments using mixed model methodology. J Anim Sci. 1986 Jul;63(1):245–258. doi: 10.2527/jas1986.631245x. [DOI] [PubMed] [Google Scholar]